Power source, charging system, and inductive receiver for mobile devices

ABSTRACT

A power source, charging system, and inductive receiver for mobile devices. A pad or similar base unit comprises a primary, which creates a magnetic field by applying an alternating current to a winding, coil, or any type of current carrying wire. A receiver comprises a means for receiving the energy from the alternating magnetic field and transferring it to a mobile or other device. The receiver can also comprise electronic components or logic to set the voltage and current to the appropriate levels required by the mobile device, or to communicate information or data to and from the pad. The system may also incorporate efficiency measures that improve the efficiency of power transfer between the charger and receiver.

CLAIM OF PRIORITY

This application claims the benefit of provisional patent applications“MOBILE DEVICE, CHARGER, AND POWER SUPPLY”, Application No. 60/810,262,filed Jun. 1, 2006; “MOBILE DEVICE, BATTERY, CHARGING SYSTEM, AND POWERSUPPLY SYSTEM”, Application No. 60/810,298, filed Jun. 1, 2006; and“SYSTEM AND METHOD FOR PROVIDING AND USING A PORTABLE INDUCTIVE POWERSOURCE”, Application No. 60/868,674, filed Dec. 5, 2006; each of whichapplications are hereby incorporated by reference herein.

FIELD OF THE INVENTION

The invention is related generally to power supplies, power sources,inductive power sources; charging systems, mobile devices, mobile devicechargers, and batteries.

BACKGROUND

There is currently a need for powering portable or mobile devices foruse in commercial, business, personal, consumer, and other applications.Examples of such devices include cellular telephones, personal digitalassistants (PDAs), notebook computers, mobile email devices, Blackberrydevices, Bluetooth headsets, music players (for example, MP3 players),radios, compact disk players, video game consoles, digital cameras,electric shavers, and electric toothbrushes. Most of these devicesinclude a rechargeable internal battery that must be first charged by anexternal power supply or charger, before the device itself can be used.The power supply typically provides direct current (DC) voltage througha special connector to the device. The power supply can then bedisconnected, and the device will continue to run for a short period oftime until the battery is depleted. The voltage and power requirementsof the different devices vary, and to date there is currently nostandardized connector for the devices. As a result of this, each mobiledevice is invariably sold or distributed bundled with its own charger.The costs associated with these multiple different types and numbers ofcharger are paid by the consumer indirectly by being incorporated intothe prices being charged for the mobile device.

The rapid increase in the total number and variety of mobile productshas meant that most people have several of the above-mentioned devices.In a typical day, that user would have to separately connect theirmultiple devices to each of their appropriate chargers for charging ofeach device. In addition, many people find it necessary to charge theirdevices in different locations such as their offices and cars. Thus,many users have purchased additional chargers for their offices andcars, for use in charging their mobile phones, notebook computers, andmusic players in those locations.

It will be evident that the above situation has caused typical users tohave a multitude of incompatible devices (i.e. power supplies andchargers) that essentially provide the same function of charging amobile device, but because of the number and variety that must be keptby the user are inconvenient to use. In many situations, users simplyforget to charge their devices, or else find they need to recharge theirdevice in situations where no appropriate charger is available. Thisleads to loss of ability to use the device when desired or needed.

In addition, when traveling way from home, mobile users have aparticular problem in that they need to pack and carry the multiplechargers for their devices. In many situations, these chargers arebulkier and heavier than the devices themselves, and use of thesedevices in foreign countries requires clumsy adaptors, and sometimesvoltage converters. This leads to a high degree of inconvenience for theever-more-mobile consumer.

In addition, the power connector for the mobile devices is often cheaplymanufactured, and a source of mechanical and electrical failure. In manyapplications, such as toothbrushes or applications where the device isexposed to water and needs to be hermetically sealed, such a physicalconnection can not be used. Thus an alternative means of powering thosetypes of devices must be used.

Several products have tried to address this situation. Some companiespropose the use of a universal charger that consists of a power supplybase unit, and interchangeable tips that both fit into the base unit andin turn fit different devices. The tip includes a customized regulatorthat sets the voltage required by the particular device. However, a usermust carry the multiple tips he or she needs for each of the variousdevices they have, and then charge each device serially by connectingthe device to the power supply. While this product reduces the overallweight of the charging tools the user must carry, the user still needsto carry and exchange the tips to connect to different devices. Inaddition, the charging of multiple devices simultaneously is often notpossible.

Realizing that a power supply typically contains a transformer forvoltage conversion, another approach is to split the transformer intotwo parts: a first part can contain the first winding and theelectronics to drive this winding at the appropriate operatingfrequency, while the second part consists of a winding where power isreceived and then rectified to obtain DC voltage. If the two parts arebrought into physical proximity to each other, power is transformed fromthe first part to the second inductively, i.e. by induction, without anyphysical electrical connection. This is the approach that is used inmany electrical toothbrushes, shavers, and other products that areexpected to be used in wet environments. However, a common problem withsuch inductive units is that the windings are bulky, which restrictstheir use in lightweight portable devices. Furthermore, to achieveadequate power transfer, the parts must be designed to fit togethersuitably so that their windings are closely aligned. This is typicallydone by molding the device casing (for example, an electric toothbrush)and its charger/holder so that they fit together in only one suitableway. However, the molded base and shape of the portable device meansthey cannot be used in a universal fashion to power other devices.

Some companies have proposed pad-like charging devices based oninductive concepts, but that also ostensibly allow for different typesof devices to be charged. These pads typically includes grids of wiresin an x and y direction, that carry an electrical current, and thatgenerate a uniform magnetic field parallel to the surface of the pad. Asecondary coil wound around a magnetic core lies on the surface of thepad and picks up the magnetic field parallel to the surface, and in thismanner energy can be transferred. However, each of these methods sufferfrom poor power transfer, in that most of the power in the primary isnot picked up in the secondary, and thus the overall power efficiency ofthe charger is very low. In addition, the magnetic cores used for theprimary and secondary are often bulky and add to the total cost and sizeof the system, and limit incorporation into many devices.

Another point to note is that, while all of the above devices allow auser to charge a device, they also require the charging device or baseunit to be electrically connected to a power source, such as a poweroutlet or a DC source. In many cases, the user may not have access tosuch a power source such as when traveling, camping, or working in anarea without access to power. However, to date, no device has beenprovided that is portable, and that allows for inductive charging ofmultiple devices with differing power requirements, and which itself canbe intermittently or occasionally charged either by an external powersource, or by other means, or that is self-powered or includes its ownpower source.

SUMMARY

A power source, charging system, and inductive receiver for mobiledevices is disclosed herein. In accordance with an embodiment, a pad orsimilar base unit comprises a primary, which creates a magnetic field byapplying an alternating current to a winding, coil, or any type ofcurrent carrying wire. A receiver comprises a means for receiving theenergy from the alternating magnetic field and transferring it to amobile or other device. The receiver can also comprise electroniccomponents or logic to set the voltage and current to the appropriatelevels required by the mobile device, or to communicate information ordata to and from the pad. The system may also incorporate efficiencymeasures that improve the efficiency of power transfer between thecharger and receiver.

In some embodiments the receiver can also comprise electronic componentsor logic to set the voltage and current to the appropriate levelsrequired by the mobile device, or to communicate information to the pad.In additional embodiments, the system can provide for additionalfunctionality such as communication of data stored in the electronicdevice or to be transferred to the device. Some embodiments may alsoincorporate efficiency measures that improve the efficiency of powertransfer between the charger and receiver, and ultimately to the mobiledevice. In accordance with an embodiment the device includes an internalbattery for self-powered operation. In accordance with other embodimentsthe device can include a solar cell power source, hand crank, or othermeans of power supply for occasional self powered operation. Otherembodiments can be incorporated into charging kiosks, automobiles, andother applications.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a pad using multiple receiver/energizer coils in accordancewith an embodiment of the invention.

FIG. 2 shows a figure of a circuit diagram in accordance with anembodiment of the invention.

FIG. 3 shows a charging pad using multiple coils in accordance with anembodiment of the invention.

FIG. 4 shows a charging pad using multiple overlapping coil layers inaccordance with an embodiment of the invention.

FIG. 5 shows the use of multiple coil types and sizes in overlapping padlayers in accordance with an embodiment of the invention.

FIG. 6 shows a receiver with an integrated battery in accordance with anembodiment of the invention.

FIG. 7 shows a coupling of receiver with a device to be charged inaccordance with an embodiment of the invention.

FIG. 8 shows a pad allowing modular or multiple connectivity inaccordance with an embodiment of the invention.

FIG. 9 shows a figure of a circuit diagram in accordance with anembodiment of the invention.

FIG. 10 shows a figure of a circuit diagram in accordance with anembodiment of the invention.

FIG. 11 shows a figure of a circuit diagram in accordance with anembodiment of the invention.

FIG. 12 shows a figure of power transfer chart in accordance with anembodiment of the invention.

FIG. 13 shows a figure of a coil layout in accordance with an embodimentof the invention.

FIG. 14 shows a figure of a coil layout in accordance with an embodimentof the invention.

FIG. 16 shows a figure of a charging pad with multiple cods inaccordance with an embodiment of the invention.

FIG. 16 shows a figure of a charging pad with movable coils inaccordance with an embodiment of the invention.

FIG. 17 shows a figure of a circuit diagram in accordance with anembodiment of the invention,

FIG. 18 shows an illustration of a means of stacking coils, inaccordance with an embodiment of the invention.

FIG. 19 shows an illustration of a device for inductive power chargingthat includes an internal battery for self-powered operation, inaccordance with an embodiment of the invention.

FIG. 20 shows an illustration of an inductive charger unit with a solarcell power source for self powered operation, in accordance with anembodiment of the invention.

FIG. 21 shows an illustration of an inductive charger unit with anincorporated communications and/or storage unit, in accordance with anembodiment of the invention.

FIG. 22 shows an illustration of a kiosk that incorporates an inductivecharger unit in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

A power source, charging system, and inductive receiver for mobiledevices is disclosed herein. In accordance with an embodiment, a pad orsimilar base unit comprises a primary, which creates a magnetic field byapplying an alternating current to a winding, coil, or any type ofcurrent carrying wire. A receiver comprises a means for receiving theenergy from the alternating magnetic field and transferring it to amobile or other device. The receiver can also comprise electroniccomponents or logic to set the voltage and current to the appropriatelevels required by the mobile device, or to communicate information ordata to and from the pad. The system may also incorporate efficiencymeasures that improve the efficiency of power transfer between thecharger and receiver.

In some embodiments the receiver can also comprise electronic componentsor logic to set the voltage and current to the appropriate levelsrequired by the mobile device. In some embodiments, the receiver canalso contain circuitry to sense and determine the status of theelectronic device to be charged, the battery inside, or a variety ofother parameters and to communicate this information to the pad. Inadditional embodiments, the system can provide for additionalfunctionality such as communication of data stored in the electronicdevice (for example, digital images stored in cameras, telephone numbersin cell phones, songs in MP3 players) or data into the device.

Embodiments can also incorporate efficiency measures that improve theefficiency of power transfer between the charger and receiver, andultimately to the mobile device. In accordance with an embodiment, thecharger or power supply comprises a switch, (for example, a MOSFETdevice or another switching mechanism), that is switched at anappropriate frequency to generate an alternative current (AC) voltageacross a primary coil, and generates an AC magnetic field. This field inturn generates a voltage in the coil in the receiver that is rectifiedand then smoothed by a capacitor to provide power to a load, with theresult being greater efficiency.

In accordance with other embodiments the coils are mounted such thatthey can move laterally within the pad and within an area of theirsegments, while continuing to be connected to their driver electronicsplaced on the edges of the area. The floating coils and the drivecircuit are sandwiched in between thin upper and lower cover layers thatact to allow the coils lateral movement while limiting verticalmovement. When a secondary is placed on the pad, the pad senses theposition of the secondary coil and moves the coils to the right positionto optimize power transfer. Magnets can be used to better orient thecoils and improve greater power transfer efficiency.

Additional embodiments are also described herein. For example, inaccordance with an embodiment the device includes an internal batteryfor self-powered operation. In accordance with other embodiments thedevice can include a solar cell power source, hand crank, or other meansof power supply for occasional self powered operation. Other embodimentscan be incorporated into charging kiosks, automobiles, computer cases,and other electronic devices and applications.

Inductive Charging System

While the above mentioned technologies describe various aspects ofinductive charging, they do not address the basic requirements that aconsumer and manufacturer desire in such a product. These include thefollowing desired features:

-   -   The pad should be able to charge a number of devices with        various power requirements efficiently. A typical number would        be 16 devices, and probably up to 4 low power (up to 5 W)        devices simultaneously. When multiple devices are being charged,        a method for energizing only those coils near a device is        preferable.    -   The same pad should be able to power low-power devices (mobile        phones, PDAs, cameras, game consoles, etc.) with power        requirements of 5 W or less, and higher-power devices such as        notebook computers (which often have a power requirement of 60 W        or higher).    -   The power transfer efficiency between the primary coil and the        secondary should be maximized. Lack of efficiency in the power        transfer would necessitate larger and heavier AC to DC power        supplies. This would add cost and decrease product        attractiveness to customers. Thus methods where the entire pad        is energized are not as attractive.    -   A simple method for verification of the manufacturer of the        secondary, and possibly information for power requirements,        should be supported as necessary to ensure product compatibility        and to provide means of product registration and licensing.    -   The EMI radiation from the system should be minimized, and        ideally, the system should radiate little or no EMI with no        device present. A charger should preferably not emit any power        until an appropriate device is brought close to the charger        itself. In this way, electric power is not wasted, and        electromagnetic power is not emitted needlessly. In addition,        accidental effects on magnetically sensitive devices such as        credit cards, disk drives and such are minimized.    -   The pad and the receiver should be reasonably simple to        construct, and cost effective. Since both parts can be        integrated into mobile devices, the overall size, weight, and        form factor should be minimized.

As used herein, the term “charger” can refer to a device for supplyingpower to a mobile or stationary device for the purpose of eithercharging its battery, operating the device at that moment in time, orboth. For example, as is common in portable computers, the power supplycan operate the portable computer, or charge its battery, or accomplishboth tasks simultaneously. In accordance with an embodiment, the mobiledevice charger can have any suitable configuration, such as theconfiguration of a flat pad. The power received by the mobile devicefrom the mobile device charger (such as the primary in the mobile devicecharger) can be rectified in the receiver and smoothed by a capacitorbefore being connected to the rechargeable battery which is representedby the load in the picture above. To ensure proper charging of thebattery, a regulator can be placed between the output of the receiverand the battery. This regulator can sense the appropriate parameters ofthe battery (voltage, current, capacity), and regulate the current drawnfrom the receiver appropriately. The battery can contain a chip withinformation regarding its characteristics that can be read out by theregulator. Alternatively, such information can be stored in theregulator for the mobile device to be charged, and an appropriatecharging profile can also be programmed into the regulator.

FIG. 1 shows a pad using multiple receiver/energizer coils in accordancewith an embodiment. In its simplest format, the mobile device charger orpower supply preferably has a substantially flat configuration, such asthe configuration of a pad 100, and comprises multiple coils or sets ofwires 104. These coils or wires can be the same size as or larger thanthe coils or wires in the mobile devices, and can have similar ordifferent shapes, including for example a spiral shape. For example, fora mobile device charger designed to charge up to four mobile devices ofsimilar power (up to 10 W each) such as mobile handsets, MP3 players,etc., four or more of the coils or wires would ideally be present in themobile device charger. The charger pad or pad can be powered by plugginginto a power source such as a wall socket. The pad can also be poweredby another electronic device, such as the pad being powered through theUSB outlet of a laptop or by the connector that laptops have at thebottom for interfacing with docking stations, or powering other devices.The pad can also be incorporated into a docking station, such as may beused by notebook computers.

A mobile device can include a receiver that includes one or more coilsor wires to receive the power from the mobile device charger. Asdescribed in further detail below, the receiver can be made part of thebattery in the mobile device or of the shell of the mobile device. Whenit is part of the mobile device shell, the receiver can be part of theinside surface of the mobile device shell or of the outside surface ofthe mobile device shell. The receiver can be connected to the powerinput jack of the mobile device or can bypass the input jack and bedirectly connected to the battery. In any of these configurations, thereceiver includes one or more appropriate coil or wire geometries thatcan receive power from the mobile device charger when it is placedadjacent to the mobile device charger. In accordance with an embodiment,the coils in the mobile device charger and/or the coils in the mobiledevices can be printed circuit board (PCB) coils, and the PCB coils canbe placed in one or more layers of PCB.

In some embodiments, the charger can also itself be built into a mobiledevice. For example, a laptop computer or other portable or mobiledevice can incorporate a charger section so that other mobile devicescan be charged as described above. Alternatively, using the same set ofcoils or wires, or a separate set of coils or wires, any mobile devicecan itself be used as a charger to power or charge other mobile devices.

In accordance with an embodiment, the mobile device charger or pad, andthe various mobile devices, can communicate with each other to transferdata. In one embodiment, the coils in the mobile device charger that areused for powering the mobile device, or another set of coils in the samePCB layer or in a separate layer, can be used for data transfer betweenthe mobile device charger and the mobile device to be charged or thebattery directly. Techniques employed in radio and networkcommunication, such as radio frequency identification (RFID) can beused. In one embodiment a chip connected to an antenna (for example, thesecondary coil or separate data antenna) or another means of transfer ofinformation can be used to provide information about, for example, thepresence of the mobile device, its authenticity (for example itsmanufacturer code) and the devices charging requirements (such as itsrequired voltage, battery capacity, and charge algorithm profile).

In accordance with an embodiment, a typical sequence for chargeroperation can be as follows: The mobile device charger can be in a lowpower status normally, thus minimizing power usage. However,periodically, each of the coils (or a separate data coil in another PCBlayer) is powered up in rotation with a short signal such as a shortradiofrequency (RF) signal that can activate a signal receiver in thesecondary such as an RF ID tag. The mobile device charger then tries toidentify a return signal from any mobile device (or any secondary) thatmay be nearby. Once a mobile device (or a secondary) is detected, themobile device charger and the mobile device proceed to exchangeinformation. This information can include a unique ID code that canverify the authenticity and manufacturer of the charger and mobiledevice, the voltage requirements of the battery or the mobile device,and the capacity of the battery. For security purposes or to avoidcounterfeit device or pad manufacture, such information could beencrypted, as is common in some RFID tags.

In accordance with various embodiment, other protocols such as NearField Communications (NFC) or Felica can be used, wherein the circuitrycontaining the ID and the necessary information is powered either by themobile device or remotely by the mobile device charger. Depending on theparticular implementation needs, Bluetooth, WiFi, and other informationtransfer processes can be used. Additional information regarding thecharging profile for the battery can also be exchanged and can includeparameters that would be used in a pre-programmed charge profile storedin the mobile device charger. However, the information exchanged couldbe as simple as an acknowledge signal that shows the mobile devicecharger that a mobile device is present. The charger can also containmeans for detection and comparison of the strength of the signal overdifferent locations on the charger. In this way, it could determine thelocation of the mobile device on the charger, and then proceed toactivate the appropriate region for charging.

In some embodiments that require greater simplicity, no communicationneed take place between the mobile device charger and the mobile device.In some embodiments the mobile device charger can sense the mobiledevice by detecting a change in the conditions of a resonant circuit inthe mobile device charger when the mobile device is brought nearby. Inother embodiments the mobile device can be sensed by a number ofproximity sensors such as capacitance, weight, magnetic, optical, orother sensors that determine the presence of a mobile device near a coilin the mobile device charger. Once a mobile device is sensed near aprimary coil or section of the mobile device charger, the mobile devicecharger can then activate that primary coil or section to provide powerto the secondary coil in the mobile device's battery, shell, receivermodule, or the device itself.

Inductive Charging Circuit

Each mobile device and its battery has particular characteristics(voltage, capacity, etc.). In order to facilitate these differentdevices with a single universal mobile device charger, several circuitarchitectures are possible, some of which are described in furtherdetail below.

FIG. 2 shows the main components of a typical inductive power transfersystem 110. The circuit illustrated is used to illustrate the principleof inductive power transfer and is not meant to be limiting to thepresent invention. In accordance with an embodiment, the charger 112comprises a power source 118, and a switch T 126 (which can be a MOSFETor other switching mechanism) that is switched at an appropriatefrequency to generate an AC voltage across the primary coil Lp 116 andgenerate an AC magnetic field. This field in turn generates a voltage inthe coil 120 in the receiver 114 that is rectified and then smoothed bya capacitor to provide power 122 to a load RI 124. For ease of use, areceiver can be integrated with a mobile device, such as integratedinside the mobile device or attached to the surface of the mobile deviceduring manufacture, to enable the device to receive power inductivelyfrom a mobile device charger or integrated into, or on its battery.

The mobile device or its battery typically can include additionalrectifier(s) and capacitor(s) to change the AC induced voltage to a DCvoltage. This is then fed to a regulator chip which includes theappropriate information for the battery and/or the mobile device. Themobile device charger provides power and the regulation is provided bythe mobile device. The mobile device charger, after exchanginginformation with the mobile device, determines the appropriatecharging/powering conditions to the mobile device. It then proceeds topower the mobile device with the appropriate parameters required. Forexample, to set the mobile device voltage to the right value required,the value of the voltage to the mobile device charger can be set.Alternatively, the duty cycle of the charger switching circuit or itsfrequency can be changed to modify the voltage in the mobile device.Alternatively, a combination of the above two approaches can befollowed, wherein regulation is partially provided by the charger, andpartially by the circuitry in the secondary.

Inductive Charger

To allow the operation of the mobile device charger regardless ofposition of the mobile device, the total area of the mobile devicecharger can be covered by coils or by another wire geometry that createsmagnetic field. FIG. 3 shows a charging pad using multiple coils inaccordance with an embodiment of the invention. As shown in FIG. 3, thepad 140 is largely covered with individual energizer coils 144.

FIG. 4 shows a charging pad using multiple overlapping coil layers inaccordance with an embodiment of the invention. This embodimentaddresses the problem of voids between the multiple coils. As shown inFIG. 4, any areas of the pad 150 with minimal magnetic field between afirst set of coils 152 can be filled by a second set of coils 154, thatare tiled such that the centers of this coil array fill the voids in theprimary set. This second set can be at a different layer of the samePCB, or in a different PCB. In each of these geometries, the sensingcircuitry can probe each location of a coil in a raster, predetermined,or random fashion. Once a mobile device on or near a coil is detected,that coil is activated to provide power to the receiving unit(secondary) of the appropriate device.

It can be seen from the above example that by providing more layers ofthe PCB with coils, or by providing coils of different geometry or size,one can obtain as much resolution or coverage as desired.

In accordance with an embodiment, to power mobile devices with powerrequirements that exceed maximum powers attainable by typical coils in asurface, the mobile device, during its hand shake and verificationprocess can indicate its power/voltage requirements to the mobile devicecharger. Several geometries for achieving power/voltage levels otherwisenot attainable from a single primary coil of the mobile device chargerare possible.

In one geometry, the power receiving unit of the mobile device hasseveral coils or receiving units that are connected such that the powerfrom several primary coils or sets of wires of the mobile device chargercan add to produce a higher total power. For example, if each primarycoil is capable of outputting a maximum of 10 Watts, by using 6 primarycoils and 6 secondary coils, a total output power of 60 Watts can beachieved. The number of primary and secondary coils need not be thesame, and a large secondary coil (receiving unit) that would be able tocapture the majority of magnetic flux produced by 6 or other number ofprimary coils or a large primary coil powering 6 or some other number ofsecondary coils can achieve the same effect. The size and shape of themultiple primary coils and secondary coils also do not need to be thesame. Furthermore, neither set of primary and secondary coils need to bein the same plane or PCB layer. For example, the primary coils in theexamples shown above could be dispersed such that some lay on one PCBplane and the others in another plane.

In another geometry, the PCS of the mobile device charger has multiplelayers, wherein coils or wire patterns of certain size and power rangecan be printed on one or more layers and other layers can contain coilsor wire patterns of larger or smaller size and power capability. In thisway, for example, for low power devices, a primary from one of thelayers will provide power to the mobile device. If a device with higherpower requirements is placed on the mobile device charger, the mobiledevice charger can detect its power requirements and activate a largercoil or wire pattern with higher power capabilities or a coil or wirepattern that is connected to higher power circuitry.

One may also achieve similar results by using a combination of thedifferent processes and geometries described above.

FIG. 5 shows the use of multiple coil types and sizes in overlapping padlayers in accordance with an embodiment of the invention. As shown inFIG. 5, the mobile device charger or pad 160 can comprise twooverlapping layers with a first layer 162 containing low power coils,and a second layer 164 containing high power coils.

Inductive Charging Receiver

To apply the inductive charging technology to current and futureelectronic devices, some of the desired characteristics include:

-   -   The receiver should provide sufficient power to the mobile or        other device with the device in proximity (e.g. several        millimeters to several centimeters) to the pad or charging        device.    -   The receiver should be of low cost, and of reasonably small size        in terms of volume and weight.    -   The receiver may in some instances be capable of being        integrated into the inside of the device by the device        manufacturer, so as to allow customers to then use the mobile        device with a charging pad.    -   The receiver may in some instances contain circuitry to identify        the presence of the receiver and the characteristics of the        charging pad.    -   The receiver may in some instances contain a means of        communication of information and data from the mobile device to        the pad.

As described above, the inductive charging pad is used to power areceiver, which in turn is used to power or to charge a portable ormobile device. In accordance with one embodiment of the receiver, thepower from the mobile device charger is emitted at a magnitude thatwould be sufficient to power any foreseeable mobile device (such as 5 or10 W for small mobile devices). The receiver that is appropriate foreach mobile device has a power receiving part that when matched to themobile device charger is able to receive sufficient power for the mobiledevice. For example a receiver for a mobile phone requiring 2.5 Wattscan be a coil with certain diameter, number of turns, wire width, etc.to allow receipt of the appropriate power. The power is rectified,filtered, and then fed into the battery or power jack of the device. Asdiscussed above, a regulator can be used before the power is provided tothe battery or the mobile device.

To save energy, the power emitted by the mobile device charger can beregulated. It is desirable to regulate the power emitted by the chargerbecause if the charger is emitting 10 W of power and the receiver isdesigned to receive 5 W, the rest of the emitted power is wasted. In oneembodiment, the receiver or the mobile device can, through an electrical(such as RF), mechanical, or optical method, inform the charger aboutthe voltage/current characteristics of the device. The primary of thecharger in the circuit diagrams shown above then can be driven to createthe appropriate voltage/current in the receiver. For example, the dutycycle of the switch in that circuit can be programmed with amicroprocessor to be changed to provide the appropriate levels in thereceiver.

In accordance with an embodiment, this can be done by a look up table ina memory location connected to a microprocessor or by using an algorithmpre-programmed into the microprocessor. Alternatively, the frequency ofthe switch can be changed to move the circuit into, and out of,resonance to create the appropriate voltage in the receiver. In analternate geometry, the voltage into the circuitry in the primary can bechanged to vary the voltage output from the receiver. Furthermore, theinduced voltage/current in the mobile device can be sensed andcommunicated to the charger to form a closed-loop, and the duty cycle,frequency, and/or voltage of the switch can be adjusted to achieve thedesired voltage/current in the mobile device.

In accordance with an embodiment, the receiver is built onto or into thebattery for the mobile device. The receiver can include one or morecoils or wires shaped to receive power from the charger. The one or morecoils or wires can be either printed on one or more PCBs. or formed fromregular wires. As described above, the receiver can also containrectifier(s) and capacitor(s) to produce a cleaner DC voltage. Thisoutput can be directly, or through a current limiting resistor,connected to one of the contacts on the battery. To avoid overchargingthe battery, a battery regulator chip can also be used. This circuitthen measures the various parameters of the battery (voltage, degree ofcharging, temperature, etc.) and uses an internal program to regulatethe power drawn from the circuit to ensure over-charging does not occur.The circuit could also include LEDs to show the receiver being in thepresence of a magnetic field from the charger, complete charge LEDsand/or audible signals.

In typical commercial and end-user applications such as cell phones,PDAs, and MP3 players, the battery could be incorporated into thebattery pack or device by the original equipment manufacturer (OEM), oras an after market size and shape compatible battery pack that canreplace the original battery pack. The battery compartment in theseapplications is typically at the bottom of the device. The user can openthe battery compartment, take out the conventional battery, replace itwith a modified battery in accordance with an embodiment of theinvention, and then replace the battery lid. The battery could then becharged inductively when the mobile device is placed adjacent a mobiledevice charger.

To enhance the ability of the receiver to receive power, it may bedesirable to minimize the distance between the charger's primary coiland the receiver's coil or wire. In order to achieve this, in accordancewith an embodiment the receiver's coil or wire can be put on the outsideof the battery pack. FIG. 6 shows a receiver with an integrated batteryin accordance with an embodiment of the invention. As shown in FIG. 6,the receiver 170 comprises the battery 182, together with the secondarycoil 172, and any rectifiers 174, capacitors 176, regulators 180necessary for proper operation of the charging receiver. If the batterycompartment lid of the device prevents a power receiving light emittingdiode (LED) to be seen, the lid can itself be replaced with asee-through lid or a lid with a light pipe that will allow the user tosee the charging indicator LED when the mobile device is placed adjacentto the charger.

In an alternative embodiment, the receiver battery can include amechanical, magnetic, or optical method of alignment of the coils orwires of the charger and mobile device for optimum power transfer. Inaccordance with an embodiment, the center of the primary in the chargercontains a magnet such as a cylinder or disk with the poles parallel tothe charger surface and the magnetic field perpendicular to the chargersurface. The receiver also contains a magnet or magnetic metal part of asimilar shape behind or in front of the center of the coil or wirereceivers. When the mobile device is placed on or adjacent to thecharger, the magnets attract and pull the two parts into alignment withthe centers of the two coils or wires aligned. The magnets do not needto be especially strong to actively do this. Weaker magnets can provideguidance to the user's hand and largely achieve the intended results.Alternatively, audible, or visual signs (LEDs that get brighter with theparts aligned), or mechanical means (dimples, protrusions, etc.) can beused for alignment.

In another embodiment, the coil or wires and the magnet in the chargerare mechanically attached to the body of the charger such that the coilcan move to align itself appropriately with the mobile device when it isbrought into close proximity to the charger. In this way, an automaticalignment of coils or wire patterns can be achieved.

In another embodiment, the receiver electronics described above arepreferably made from flexible PCB which can be formed into a curvedshape. Such a PCB can be placed on the surface of a battery pack that isnot flat or that has a curved shape. The curve on the battery or back ofa mobile device battery lid can be matched to a curved primary in themobile device charger and be used for alignment. One example of usage ofthis embodiment can be for example flashlights that have circularhandles the batteries can be charged with coils on the side of circularbatteries, or circling the cylindrical battery. Similarly, the mobiledevice charger can have a curved shape. For example, the charger surfacecan be in the shape of a bowl or some similar object. A mobile devicethat may have a flat or curved back can be placed into the bowl. Theshape of the bowl can be made to ensure that the coil of the mobiledevice is aligned with a primary coil to receive power.

In another embodiment, the primary can be incorporated into a shape suchas a cup. A mobile device can be placed into the cup standing on end andthe receiver could be built-in to the end of the mobile device (such asa mobile phone) or on the back or circumference of the device. Thereceiver can receive power from the bottom or wall of the cup.

In another embodiment, the primary of the charger can have a flat shapeand the mobile devices can be stood up to receive power. The receiver isbuilt into the end of the device in this case and a stand or somemechanical means can be incorporated to hold the device while beingcharged.

In another embodiment, the charger can be made to be mounted on a wallor a similar surface, vertically or at an angle (such as on a surface ina car), so as to save space. The charger could incorporate physicalfeatures, magnets, fasteners or the like to enable attachment or holdingof mobile devices to be charged. The devices to be charged can alsoincorporate a retainer, magnet, or physical shape to enable them to stayon the charger in a vertical, slanted, or some other position. In thisway, the device could be charged by the primary while it is near or onit.

For those applications where the lid of the battery compartment or thebottom part of the mobile device is made from a metal, a replacementnon-metallic lid or backing can be used. Alternatively, the col can beattached to the outside of the metal surface. This allowselectromagnetic (EM) fields to arrive at the power receiver coil orwires. The rest of the receiver (i.e. circuitry) can be placed behind ametal for the receiver to work. In some other applications where thebattery has metal parts, these parts may interfere with the EM field andthe operation of the coil in the receiver. In these cases, t may bedesirable to provide a distance between the metal in the battery and thecoils. This could be done with a thicker PCB or battery top surface.Alternatively, to provide additional immunity, ferrite material (such asthose provided by Ferrishield Inc.) can be used between the receiver andthe battery to shield the battery from the EM fields. These materialscan be made so as to be thin, and then used during the construction ofthe integrated battery/receiver.

In another embodiment, the receiver in the battery also includes a meansfor providing information regarding battery manufacturer, requiredvoltage, capacity; current, charge status, serial number, temperature,etc. to the charger. In a simplified embodiment, only the manufacturer,required voltage, and/or serial number is transmitted. This informationis used by the charger to adjust the primary to provide the correctcharge conditions. The regulator in the receiver can then regulate thecurrent and the load to charge the battery correctly and can end chargeat the end. In another embodiment, the receiver can control the chargingprocess fully depending on the time dependent information on batterystatus provided to it. Alternatively, the charging process can becontrolled by the charger in a similar manner. As described above, theinformation exchange between the charger and the receiver can be throughan RF link or an optical transmitter/detector, RFID techniques.Near-Field Communication (NFC), Felica, Bluetooth, WiFi, or some othermethod of information transfer. Similarly, the receiver could sendsignals that can be used by the charger to determine the location of thereceiver to determine which coil or section of the charger to activate.The communication link can also use the same coil or wires as antennafor data transfer or use a separate antenna. In some embodiments thereceived can use the actual capabilities of the mobile device (forexample, the built-in Bluetooth or NFC capabilities of mobile phones) tocommunicated with the charging pad.

As described above, in accordance with some embodiments the receiver canbe integrated into the body of the device itself at a location that maybe appropriate and can be exposed to EM radiation from outside. Theoutput of the receiver can be routed to the electrodes of the batteryinternally inside the device and appropriate circuitry inside the devicecan sense and regulate the power. The device can include LEDs, messages,etc, or audible signs that indicate to the user that charging isoccurring or complete or indicate the strength of the received power(i.e. alignment with a primary in the charger) or the degree of batterycharge. In other embodiments, the receiver is built into an inner orouter surface of a component that is a part of the mobile device's outersurface where it would be closest to the charger. This can be done asoriginal equipment or as an after-market item. The component can be thelid of the battery pack or the bottom cover of the mobile device. In yetother embodiments, the receiver can be integrated into the back or frontof the battery compartment or an interchangeable shell for the mobiledevice for use in after-market applications. For example, in a mobilephone application, the back battery cover or shell can be removed andreplaced with the new shell or battery cover with the receiver built in.FIG. 7 shows a coupling of receiver with a device to be charged inaccordance with an embodiment of the invention. As shown in FIG. 7, theoriginal mobile phone setup 190 includes a device 192 with shell 194 andpower jack 196. The after-market modification 200 replaces the originalshell with a combination shell 210 that includes the necessary receivercoils and batter couplings. The contacts from this circuitry can thenmake direct contact to the battery electrodes inside the mobile deviceor to some contact points inside the mobile device if such contactsexist or become provisioned by the device manufacturer duringmanufacture. Alternatively, the receiver may be a component (such as ashell) that has a connector that plugs into the input power jack of themobile phone. The receiver can be fixed to, or detachable from, themobile device. This could be achieved by having a plug that is attachedeither rigidly or by a wire to the receiver (shell). Alternatively, thereplacement receiver (shell) could be larger than the original shell andextend back further than the original shell and contain the plug so thatwhen the receiver (shell) is attached, simultaneously, contact to theinput power jack is made. Alternatively, the receiver (shell) can have apass-through plug so that while contact is made to this input powerconnector, the connector allows for an external regular power supplyplug to be also used as an alterative. Alternatively, instead of apass-through, this part could have a power jack in another location inthe back so that a regular power supply could be used to charge thebattery. In cases where the connector to the device performs otherfunctions such as communication to the device, a pass-through connectorcan allow communication/connectivity to the device.

In accordance with another embodiment, the replacement receiver (i.e.the replacement shell) or the plug in unit, in addition to the powerreceiver components and circuitry, can include additional circuitry thatcan provide further functionalities to the mobile device. These couldinclude, for example, the ability to exchange data through Bluetooth,WiFi, NFC, Felica, WiMax, RFID, or another wireless or opticalmechanism. It could also provide extended functionalities such as GlobalPositioning System (GPS) location information, flashing lights,flashlight, or other decorative or electronic functions. As describedabove, various methods for improving coil alignment, or location,battery manufacturer, or battery condition information transfer can alsobe integrated into the receiver or replacement shell.

In another embodiment, the receiver is supplied in the form of aseparate unit that is attached to the input jack of the mobile device orintegrated into a secondary protective skin for the mobile device. Manyleather or plastic covers for mobile phones, cameras, and MP3 playersalready exist. The primary purpose of these covers is to protect thedevice from mechanical scratches, shocks, and impact during daily use.However, they often have decorative or advertising applications. Inaccordance with one embodiment, the receiver is formed of a thin PCBwith the electronics formed thereon, and the receiver coil or wire thatis attached to the back of the device and plugs into the input jacksimilar to the shell described above. Alternatively, it can be connectedthrough a flexible wire or flexible circuit board that is routed to aplug for the input power jack.

In another embodiment, the receiver can be a separate part that getsplugged into the input jack during charging and is placed on the chargerand can then be unplugged after charging is finished.

In yet another embodiment, the receiver is built in the inside oroutside surface or in between two layers of a plastic, leather,silicone, or cloth cover for the mobile device and plugs in or makescontact to the contact points on the device.

It will be noted that certain devices such as notebooks and some musicplayers have metal bottom surfaces. The methods described above forchanging the back surface or use of a plug in the mobile device or asecondary skin with an integrated receiver is particularly useful forthese applications. As described previously, the effect of the metalsurface can also be minimized, if necessary, by increasing the distancebetween the wires of the receiver and the metal surface or by placing aFerrite layer in between the receiver and the metal bottom.

It is also noted that the use of methods such as curving the receiver orintegrating magnets, LEDs, audio signals or messages, etc. foralignment, or methods for location, manufacturer or charging conditionidentification, as described above are possible with all embodiments ofthe present invention described above. In any of the above cases, thecharger can contain lights, LEDs, displays, or audio signals or messagesto help guide the user to place the mobile device on a primary coil formaximum reception, to show charging is occurring, and to show the deviceis fully charged. Displays to show how full the battery is or otherinformation can also be incorporated.

Portable Inductive Charging Pad

In accordance with an embodiment a flexible mobile device charger isprovided in the shape of a pad that can be folded or rolled up forcarrying. In one implementation of the invention, the electronics of thecharger are placed on a thin flexible PCB or the coils are made of wiresthat can be rolled up or shaped. The electronics components made ofsilicon chips, capacitors, resistors and the like may not be flexiblebut take up very little space. These rigid components can be mounted ona flexible or rigid circuit board, while the main section of the padcontaining the coils or wires for energy transfer could be made to beflexible to allow conformity to a surface or to be rolled up. Thus thepad resembles a thin mouse pad or the like.

In some cases, it may be advantageous to the user to have a mobiledevice charger that is extendible in functionalities. The cases includebut are not limited to:

-   -   A user may purchase a mobile device charger for charging a        single low power device but, at a later stage, may want to        extend the capability to charge more devices simultaneously    -   A user may purchase a mobile device charger for charging one or        more low power devices but may want to charge more low power or        high power devices.    -   A user may buy a mobile device charger that can charge one or        more low-power or high-power devices and later wish to have the        communication or local storage, or a rechargeable battery, or        means of power generation such as solar panels or some other        capability, added to the charger.

In all of the cases above and others, it can be useful to have a modularapproach to expand the capabilities of the mobile device charger. FIG. 8shows a pad 220 allowing modular or multiple connectivity in accordancewith an embodiment of the invention. In this case, the user can purchasea first unit 222 that is powered by an electric outlet 224. However,interconnects 226 for power and data are provided so that additionalunits 228, 230 can simply fit or plug into this first one directly orindirectly and expand the capabilities as the customers needs grow. Datacommunications and storage units 234 can also be attached in a modularfashion. This approach would enable the customer to use the technologyat a low cost entry point and grow his/her capabilities over time.

Some of the electronics devices that can benefit from these methodsinclude: mobile phones, cordless phones, personal data assistants(PDAs), pagers, mobile electronic mail devices, Blackberry's, MP3players. CD players, DVD players, game consoles, headsets. Bluetoothheadsets, head-mounted displays, GPS units, flashlights, watches,cassette players, laptops, electronic address books, handheld scanningdevices, toys, electronic books, still cameras, video cameras, filmcameras, portable printers, portable projection systems, IR viewers,underwater cameras or any waterproof device, toothbrushes, shavers,medical equipment, scientific equipment, dental equipment, militaryequipment, coffee mugs, kitchen appliances, cooking pots and pans, lampsor any battery, DC, or AC operated device.

In addition, inductive power transfer can provide power to devices thatare not so far battery operated. For example, a mobile device charger inthe shape of a pad placed on a desk or a kitchen table can be used topower lamps or kitchen appliances. In one embodiment for the use in akitchen, a flat charger, such as a pad, placed on or built into acounter can allow the chef to place devices on the charger to beinductively charged during use and simply place them away after use. Thedevices can be, for example, a blender, mixer, can opener, or even pot,pan, or heater. This can eliminate the need for a separate cooking andwork area it will be noted that placement of a metal pan close to theinductive pad could directly heat the pan and the contents while keepingthe charger surface cool. Due to this reason, inductive kitchen rangeshave been commercialized and shown to be more efficient than theelectric ranges that work by resistive heating of a coil.

In another embodiment, rather than direct heating of metal pans bynearby inductive fields, cooking pans may include a receiver and heatingor even cooling elements. Once placed on a charger, the pan would heatup or cool down as desired by a dial or the like on the pan allowingprecise temperature control of the pan and the contents.

Similarly, in an office or work area setting, if a charger is readilyavailable for charging mobile devices, it can also be used to power uplamps for illumination of the desk or used to power or charge officeappliances, such as fax machines, staplers, copiers, scanners,telephones, and computers. In one embodiment, the receiver can be builtinto the bottom of a table lamp and the received power would be used topower the incandescent or LED lamp.

In another embodiment, a mug, cup, glass, or other eating appliance suchas a plate can be fitted with a receiver at its bottom. The receivedpower can be used to heat the mug, etc. with a heating coil thus keepingbeverages or food warm to any degree desired. Furthermore, in accordancewith an embodiment, by use of devices such as thermoelectric coolers thecontents could be cooled or heated as desired.

Similarly, many children's toys often run out of battery due to extendeduse or simple forgetfulness to turn the device off. Often thesebatteries are included inside a battery compartment that for safetyreasons can only be opened by a screwdriver. Inclusion of the receiverinto toys could reduce the need to change the device batteries and allowrecharging with a much simpler method.

In another implementation, the receiver can be built into medicaldevices that are implanted or inserted in the body. Since batteries inthese devices such as pace makers, cochlear implants, or othermonitoring devices may need periodic charging, inductive power transfercan provide an ideal non-contact method for charging and testing theperformance of the devices (i.e. check up) or downloading data that thedevices have logged.

In another implementation, some active RFID tags include batteries thatcan send out information about the status or location of a package orshipment. An inexpensive method for charging these tags would be toinclude a receiver with each tag. Thus, a charger can be used to poweror charge these RFID tags.

It will be noted that the effective working distance of the inductivecharger is dependent on the power and the frequency of the source. Byincreasing the frequency to several or tens of MHz, one can obtain aworking distance of several inches or feet depending on the applicationfor the technology. It will also be noted that any of the aboveembodiments that eliminate the input power jack are especially importantbecause they add to product reliability by removing a source ofmechanical or environmental failure, in addition, elimination of thejack is imperative for water proof applications and for extra safety.

Efficiency Enhancements in Circuit Design

In accordance with an embodiment of the invention, in order for thepower efficiency to be maximized and to minimize losses in the coil, thecoils should be manufactured to have as low a resistance as possible.This can be achieved by use of more conductive material such as gold,silver, etc. However in many applications, the cost of these materialsare prohibitive. In practice, reduced resistivity can be obtained byusing thicker copper-clad PCBs. Most common PCBs use 1-2 oz copper PCBs.In accordance with some embodiments the coil PCB used for the wirelesscharger can be made from PCBs clad with between 2 and 4, or even 6 ozcopper. The process of manufacture of the PCB can also be optimized toachieve higher conductivity. For example, sputtered copper has a higherconductivity than rolled copper and is typically better for thisapplication. In operation, the coil and the circuitry demonstrates aresonance at a frequency determined by the parameters of the design ofthe coil (for example, the number of windings, coil thickness, width,etc.). However, previous work has concentrated on circuits driven bysquare waves with a MOSFET. This approach has the disadvantage thatsince a square wave is not a pure sinusoid, it produces harmonics. Theseharmonics are undesirable because:

-   -   The PCB coil produces optimum power transfer efficiency at a        particular frequency. The harmonics in the primary signal are        not transferred as efficiently and decrease the overall system        efficiency.    -   The rapid voltage change in the leading and falling edge of the        square wave creates oscillations that create further harmonics        resulting further EMI.    -   The harmonics radiated by the primary create higher frequency        components that contribute to the EMI that is more radiative        (due to higher frequency). It is desirable to limit the        frequency range of the operation of the overall system to as low        a frequency as possible while maintaining the other requirements        of the system (such as sufficient working distance, etc.). So        these harmonics must be avoided.    -   At the instance of switch turn-on and turn-off, the change in        the in-rush current to the coil causes huge voltage swings        across the coil for a short period of time. All the power is        transferred to the secondary during these times that are short.

Previous attempts to achieve 90% transfer efficiency with PCB coilprimary and receiver have used a laboratory power supply to drive theircircuit. While this approach has demonstrated the higher efficiency thatcan be achieved with a sinusoidal voltage on the coil, such powersupplies are complex, costly, and too large to be able to be used forany practical charger application.

In accordance with an embodiment of the present invention, a capacitoris added in parallel to the drain/source contacts of the MOSFET. FIG. 9shows a figure of a circuit diagram 240 in accordance with anembodiment. The coil in the wireless charger system is driven byswitching the FET at the resonance frequency of the circuit when thereceiver is present. Without the receiver nearby, the circuit is detunedfrom resonance and radiates minimal EMI. The capacitor 244 acts as areservoir of energy that discharges during switch off time and enhancesenergy transfer.

By way of example, in accordance with an embodiment that uses anIRFR0220 chip as a FET and use 4 Oz, copper coils with 9 turns and 1.25″diameter, the circuit in FIG. 2 above, can be loaded with RL of 10 Ohmand tuned to operate at 1.3 MHz. With matching coils in the primary andsecondary, without capacitor C, total circuit efficiency of the circuitincluding the clock and FET driver circuit approaches 48%. Addition of a1600 pF capacitor in parallel to the FET increases the total circuitefficiency to 75% (a better than 50% increase in efficiency), whilesimultaneously decreasing the voltage across the FET and also theharmonics in the circuit. The coil to coil transfer efficiency with thecapacitor placed in parallel with the FET is estimated to beapproximately 90%. The advantages of this approach include,

-   -   High efficiency (˜90% coil to coil).    -   Low ringing oscillation and EMI.    -   Simplicity and low cost.    -   Lower FET source-drain voltage swing allowing use of a larger        selection of FETs.

In many applications, it is also desired that the pad and the receiverare arranged so that the pad does not emit power unless the receiver isnearby. FIGS. 10 and 11 show figures of circuit diagrams in accordancewith an embodiment of the invention. In addition to high efficiency, onemethod that is required for minimizing EMI and maintaining high overallefficiency is the ability to recognize the presence of a secondarynearby, and then turning on the pad only when appropriate. Two methodsfor this are shown in FIGS. 10 and 11.

As shown in FIG. 10, in accordance with one embodiment, the pad circuit260 incorporates a micro control unit (MCU1) 266 that can enable ordisable the FET driver 268. The MCU1 receives input from another sensormechanism that will provide information that it can then use to decidewhether a device is nearby, what voltage the device requires, and/or toauthenticate the device to be charged.

One of the sensor mechanisms for this information are through the use ofan RFID reader 280 that can detect an RFID tag of circuit and antenna inthe secondary (i.e. device to be charged). The information on the tagcan be detected to identify the voltage in the secondary required and toauthenticate the circuit to be genuine or under license. The informationon the tag can be encrypted to provide further security. Once a devicecontaining the tag is nearby the pad, the RFID reader can be activated,read the information on the tag memory and compare with a table todetermine authenticity/voltage required or other info. This informationtable can also reside on the MCU1 memory. Once the information is readand verified, the MCU1 can enable the FET driver to start driving thecoil on the pad and to energize the receiver.

In another embodiment the MCU1 relies on a clock 270 to periodicallystart the FET driver. The current through the FET driver is monitoredthrough a current sensor 264. Several methods can be implemented withthis implementation, including for example:

-   -   A small resistor can be placed in series with the FET to ground        contact. The voltage across this resistor can be measured by a        current sensor chip, such as a Linear Technology Current Sense        Amplifier part number LT1787.    -   A Hall sensor, such as a Sentron CSA-1A, that measures the        current from a wire running under it, can be placed on top of        the PCB line from the FET to the ground to measure the current        without any electrical connection to the circuit. The advantage        of this approach is that no extra resistor in series with this        portion of the circuit is necessary reducing the impedance.    -   Other techniques may be used to measure the current.    -   A Hall sensor or a Reed switch can sense a magnetic field. If a        small magnet is placed inside the receiver unit of the system, a        Hall sensor or Reed switch can be used to sense presence of the        magnet and can be used as a signal to start the FET.    -   Other capacitance, optical, magnetic, or weight, etc. sensors        can be incorporated to sense the presence of a secondary or        receiver and to begin the energy transfer process,

FIG. 11 shows a figure of a circuit diagram 290 in accordance with anembodiment of the invention. In accordance with an embodiment, the MCU1can periodically start the FET driver. If there is a receiver nearby, itcan power the circuit. The regulator 296, or another memory chip in thecircuit can be programmed so that on power-up, it draws current in apre-programmed manner. An example is the integration of an RFIDtransponder chip in the path, such as ATMEL e5530 or another inexpensivemicrocontroller (shown here as MCU2 294), that upon power-up modulatesthe current in the secondary that can then be detected as currentmodulation in the primary. As with the previous example, other sensors,such as an RFID antenna 292 can also be used to provide positional andother information.

FIG. 12 shows a figure of a power transfer chart 300 in accordance withan embodiment of the invention, illustrating transferred power as afunction of offset between coils.

Efficiency Enhancements in Coil Layout

An important aspect of power transfer efficiency relates to thealignment of coils with respect to each other. FIGS. 13 and 14 showfigures of a coil layout in accordance with an embodiment of theinvention, if position independence is required, the pad PCB can bepatterned with a coil pattern to cover the full area. FIG. 13 shows apad type charger 310 including a layer of coils 312 with minimal spacing314 between the coils. Each coil has a center 316 associated with it.The power transfer for a 1.25″ diameter coil as the center of thesecondary is offset from the center of primary. The power drops off to25% of the maximum value when the two coils are offset by a coil radius.As described above, in order to better keep the coils aligned, use ofmagnets centered on the primary and the secondary coil can provide anautomatic method of bringing the two parts into alignment.

In order to produce uniform fields, a number of coils around thesecondary would typically need to be turned on to produce a field.However, with such a pattern, if a secondary coil is placed in betweentwo primary coils, the voltage is still not optimized. Research hasshown that to obtain uniform fields, three layers of coil patternsoffset with respect to each other are required.

FIG. 14 shows a pad-type charger 320 with two of the three layers 322,324 required to achieve position independent magnetic field pattern. Fora secondary placed at the center of the circle, all the coils nearby (inand around the circle 328) will need to be turned on to achieve auniform field in the desired location 326. While this approach solvesthe offset issue and can be used to provide position independence, itdoes not produce high transfer efficiency. The reason is that ten ormore coils have to be turned on near the secondary center to create theuniform field in that area, which in turn leads to inefficient powertransfer.

Efficiency Enhancements in Independent Coil Movement

In accordance with some embodiments, techniques are included to providehigh transfer efficiency while maintaining position independence. FIG.16 shows a figure of a charging pad with multiple coils in accordancewith an embodiment of the invention. The area of the pad 330 is dividedinto a plurality of, or multiple segments 332, that are bounded 336 by awall or physical barrier, or simply some tethering means with nophysical walls but that otherwise restrict movement to within thesegment. The coils 334 are mounted such that they can move laterally, orfloat, within the area of their segments while continuing to beconnected to the drive electronics placed on the edges of the area. Inaccordance with an embodiment, the floating coils and the drive circuitare sandwiched between thin upper and lower cover layers that act toallow the coils lateral movement while limiting vertical movement. Whena secondary is placed on the pad, the pad senses the position of thesecondary coil and moves the coils to the right position to optimizepower transfer.

FIG. 16 shows a figure of a charging pad with movable coils inaccordance with an embodiment of the invention. When the mobile device,for example a cell phone 340, is placed on the pad 330, the nearest coilmoves 342 within its segment to better orient itself with the mobiledevice. In accordance with one embodiment, the method used for achievingthis is by attaching a magnet to the bottom center of each coil in thepad. A matching magnet at the center of the receiver coil attracts theprimary magnet nearby and centers it automatically with respect to thesecondary.

In accordance with an embodiment, each coil in this configuration can besuspended by the wires carrying power to the coil or by a separatewire/spring or by another mechanism so that each coil can move freely inthe plane of the pad while it can receive power from an individual orshared driving circuit. In order to facilitate movement, the surface ofthe coils or the bottom surface of the top layer for the base unit (thearea where the coils move against) or both layers can be made smooth byuse of a low friction material, attachment of a low friction material,or lubrication. The wire/spring or current carrying mechanism describedabove can also be used to center each coil in an area at the center ofdesired movement sector for each coil. In this way, without a secondarycoil in the vicinity, each coil in the base unit stays at the centrallocation of its sector and responds and moves to match a secondary coilwhen a device is brought nearby. Overlap of movement between adjacentbase unit coils can be controlled by limiting movement through limitinglength of current carrying wires to the coil, arrangement of thesuspension, or spring, or placement of dividing sectors, pillars or byany other mechanism.

In another embodiment, the pad will include a method for detecting thepresence of the mobile device/receiver and taking appropriate action toturn on the coil and/or to drive the coil with the appropriate patternto generate the required voltage in the receiver. This can be achievedthrough incorporation of RFID, proximity sensor, current sensor, etc. Asequence of events to enable position independence and automatic padturn-on can be:

-   -   Multiple movable coils are used to cover the pad surface area.    -   The coils in the pad are normally off and periodically powered        up sequentially to sense whether the secondary is nearby by        measuring the current through the primary coil. Alternatively,        proximity sensors under each section can sense the presence of a        magnet or change in capacitance or other parameter to know where        a device is placed. RFID techniques with localized antennas        under each section or such can also be used.    -   Once a device is identified as placed in a section, the pad can        interrogate the device through one of the processes described        earlier to authenticate and to understand its voltage/power,        etc, requirements.    -   The MCII unit uses the information received above to set the PWM        pattern which it will use to drive the FET drive to produce the        appropriate voltage in the receiver    -   The board continues to ‘search’ for other devices on the pad by        scanning coils or using the RFID system, etc. and then turn on        other coils as appropriate.    -   The pad also use the monitoring to find out when and if the        first mobile device is removed from the pad or end of charge is        reached.

Efficiency Enhancements in Coil Registration and Switching

In accordance with an embodiment, a global RFID system that wouldidentify the approach of a mobile device to the pad can be used to ‘wakeup’ the board. This can be followed by sequential polling of individualcoils to recognize where the device is placed in a manner similar todescribed above. Other embodiments of the invention provide safeguardsagainst false charging of objects placed on the base unit. It is knownthat a metal object placed on coils such as the ones in the base of thecharger system would cause current to flow in the primary and transferpower dissipated as heat to the metal object. In practical situations,this would cause placement of keys and other metal objects on the baseunit to trigger a start and to needlessly draw current from the baseunit coil and possibly lead to failure due to over-heating. To avoidthis situation, in a system as described above, the switching of voltageto the coil would not start unless an electronic device with averifiable RFID tag is nearby thereby triggering the sequence of eventsfor recognizing the appropriate coil to turn on and operate. In analternate geometry, the total system current or individual coil currentis monitored, and, if a sudden unexpected drawn current is noticed,measures to investigate further or to shut down the appropriate coilindefinitely or for a period of time or to indicate an alarm would betaken.

In another embodiment, the regulators or battery charging circuit inmobile devices or regulator in a receiver electronics typically has astart voltage (such as 5V) that is required to start the chargingprocess. Once the battery charge circuit detects the presence of thisvoltage, it switches on and then proceeds to draw current at a presetrate from the input to feed the battery for charging. The batterycharger circuits operate such that an under or over voltage at the startwill prevent startup. Once the startup occurs, the voltage at thebattery charger output is typically the voltage of the battery anddepends on the state of charge, but is for example 4.4V to 3.7V or lowerfor Lithium-Ion batteries. With a wireless charge system such asdescribed here, the voltage on the secondary is highly dependent onrelative position of the primary and secondary coil as shown in FIG. 5.Since typically the start voltage of the battery charger is within anarrow range of the specified voltage, under-voltage and over-voltage inthe receiver coil due to mis-alignment or other variation will result inshutdown of the battery charger circuit.

Efficiency Enhancements in Coil Voltage Clamping

FIG. 17 shows a figure of a circuit diagram 350 in accordance with anembodiment of the invention. In accordance with one embodiment, a Zenerdiode 352 is incorporated to clamp the maximum voltage at the output ofthe receiver prior to the regulator or battery charger circuit, as shownin FIG. 17. Using a Zener allows more insensitivity to placement betweenthe primary and secondary coil while maintaining the ability to chargethe device. For example, the drive pattern on the primary can be set sothat when the primary and secondary coil are aligned, the voltage on thesecondary is above the nominal voltage for the battery charger startup.For example, for a 5V startup, the voltage at center can be set for 6 or7 volts. In this way, the Zener can be chosen to have an appropriatevalue (5V) and clamp the voltage at this value at the input to thebattery charger unit while the coils are centered or mis-aligned. Oncethe battery charger starts operation after detection of the appropriatevoltage at the input, the battery charger circuitry would pull thevoltage at this point to the pre-programmed voltage or voltage of thebattery. In this way, the use of Zener diode would enable lesssensitivity to position and other operational parameters in wirelesschargers and would be extremely useful.

Efficiency Enhancement in Coil Stacking

FIG. 18 shows an illustration of a means of stacking coils, inaccordance with an embodiment of the invention. In accordance with anembodiment, to achieve higher flux densities, a coil is constructed withtwo or more layers, for example by using two or more layers of printedcircuit board. Multiple layer boards can be used to allow compactfabrication of high flux density coils. By altering the dimensions ofthe coil in each layer (including the thickness, width, and number ofturns) and by stacking multiple layers, the resistance, inductance, fluxdensity, and coupling efficiency for the coils can be adjusted so as tobe optimized for a particular application.

In accordance with an embodiment, a transformer consisting of two PCBcoils separated by a distance has many parameters that are defined bythe design of the coil, including:

-   -   R₁ is the primary winding resistance,    -   R′₂ is the secondary winding resistance referred to the primary,    -   R_(L) is the resistive load,    -   L_(n1) is the primary leakage inductance,    -   L′_(n2) the secondary leakage inductance referred to the        primary,    -   L_(n2) is the primary mutual inductance,    -   C₁ is the primary winding capacitance,    -   C′₂ is the capacitance in the secondary winding referred to the        primary,    -   C₁₂ is the capacitance between primary and secondary windings,        and    -   n is the turns ratio.

In accordance with the embodiment shown in FIG. 18, a multi-layer PCBcoil 356 is created in separate PCB layers 357, which are then connected358, and manufactured together via common techniques used in PCBfabrication, for example by use of vias and contacts. The resultingoverall stack is a thin multi-layer PCB that contains many turns of thecoil. In this way, wide coils (low resistance) can be used, while theoverall width of the coil is not increased. This technique can beparticularly useful for cases where small x-y coil dimensions aredesired, and can be used to create higher flux densities and moreefficient power transfer.

Inductive Charger with Self-Powered Operation

FIG. 19 shows an illustration of a device for inductive power chargingthat includes an internal battery for self-powered operation, inaccordance with an embodiment of the invention. As shown in FIG. 19, aninductive charging unit such as an inductive pad 360 includes arechargeable battery 364. The unit is normally operated with, or isoccasionally coupled to, power input from an electrical outlet, or froma do source such as a car 12 volt dc outlet, or from an outlet in anairplane or an external dc source, or from another power source such asthe USB outlet from a computer or other device. Alternatively, the powercan come from a mechanical source such as a windmill, or a human-poweredcrank handle. The unit can include coils 362 that are energized totransfer power to secondary coils in mobile electronics devices such asmobile phones, MP3 players, radios, cd players. PDAs, and notebookcomputers. At the same time, the input power charges the rechargeablebattery inside the unit itself. When the external power source to theunit is disconnected, or when no input power is provided, the unitautomatically switches its operation from its charged internal battery.Alternatively, the units operation can be switch-operated by user. Inthis way, users can continue to charge their devices by placement on theunit without any outside power source. This use can continue until theexternal power is restored or until the internal battery is completelydischarged.

The ability of the unit to continue charging would depend on thecapacity of the battery included. Thus, for example, with a 1500 mAHinternal battery, the unit would be able to charge a mobile phone with a1000 mAH battery completely if the losses due to conversion efficiency,operation of the circuitry in the unit, and other losses are up to 500mAH.

In other embodiments of the invention, the unit can be powered by otherpower sources such as a fuel cell that generates power from methanol orother sources. The unit can also be connected to the electric gridthrough an outlet or to an external DC power source such as power froman outlet in a car or airplane or be itself charged or poweredinductively by another unit. However, when not connected to outsidepower, the unit can be powered by its internal power generator from thefuel cell and can charge devices placed on it inductively.

FIG. 20 shows an illustration of an alternate embodiment of an inductivecharger unit or pad 370 with a solar cell power source for self poweredoperation, in accordance with an embodiment of the invention. As shownin FIG. 20, the surface of the unit can be covered by a solar panel orsolar cell 376. In normal operation, the unit can be powered-up orcharged by connection to an electric outlet or external DC source. Butwithout external electric power, the panel generates electric power thatis used to power the charger which in turn can charge devices placed onit through the inductors in the unit. In some embodiments the unit canalso include a rechargeable battery 374 that can be charged when theunit is either connected to external electric power or charged by thesolar cells on the surface of the unit. This battery can then operatethe unit when the unit is either not connected to external electricpower or the solar cell is not generating enough power to run the unitsuch as during operation at night.

FIG. 21 shows an illustration of an inductive charger unit with anincorporated communications and/or storage unit, in accordance with anembodiment of the invention. As shown in FIG. 21, in accordance withsomeembodiments the charger, including for example the regular charger 380,and the solar-cell powered charger 382, can further comprise an optionalcommunications and/or storage unit, for storage of data and transmissionof data to and from a mobile device being charged. Examples ofcomponents that can be incorporated include Bluetooth, Near-fieldCommunications (NFC), WiFi, WiMax, wireless USB, and proprietarycommunications capabilities, including means of connecting to theinternet.

Inductive Charger Applications and Kiosk

The technology described herein may also be used for other applications,in some applications, it may be desirable to build the inductive (asdescribed above) or wire free charger into a case for an electronicdevice, a briefcase, or other carrier such as a box, holder, orcontainer in a car or other wise. An example can be a brief case, handbag, or back pack where the bottom part or the outside surface has anintegrated charger. Any device enabled to receive power from such acharger (device containing coils and the appropriate electronics toreceive power or with appropriate contacts for wire free charging) canbe placed on or inside such a briefcase and be charged. The chargingcircuitry can be powered by plugging the briefcase, handbag, or backpack into an outlet power or having internal batteries that can becharged through power from a wall plug or by themselves beinginductively charged when the briefcase, handbag, or backpack is placedon an another inductive or wire free charger. Uses can be applied to anybag, container, or object that can be used to essentially charge orpower another device. This first object can itself be charged or poweredthrough an outlet directly by wires or wirelessly through an inductiveor wire free charging system. As an alternative, the first object (thecharger) can be powered by solar cells, Fuel cells, mechanical methods(hand cranks, pendulums, etc.).

In all of the above case, it is possible for the functions of theinductor or wire free charger and the power source for the charger(battery, fuel cell, solar cell, etc.) to be separated. Furthermore, insome cases, the charger part can be separated from a portable powersource to operate it (such as a rechargeable battery) which is in turnpowered or charged by another source (power outlet, fuel cell, solarcell, mechanical source, etc.). The three parts can be in the sameenclosure or area or separate from each other.

An additional example may be an after market inductive or wire freecharger for a car where the inductive or wire free charger or padincluding a solar cell on the pad or in another area and connected tothe pad by wires is used to charge mobile devices. Such a device placedon the dashboard or tray between seats or a special compartment can beused to charge a number of devices such as phones, MP3 players, cameras,etc. Devices such as GPS navigation systems, radar detectors, etc, canalso be powered from such a device. In another application, mugs, cups,or other containers with a receiver circuitry and means of heating orcooling the contents can be used in combination with the inductivecharger to keep the contents hot or cold. A dial or buttons on the cupor container can set the temperature. The charging device or pad canalso contain rechargeable batteries that allow the device or pad tostore energy and operate in the absence of any external power ifnecessary.

Other applications of this technology include clothing, jackets, vests,etc. that have an integrated inductive charger such that a user canpower or charge a device by simply placing it on or near a pocket or anarea where wireless inductive power is available. The jacket or clothingcan in turn be powered by solar cells, Fuel cells, batteries, or otherforms of energy. It can also be powered by batteries that would berecharged through solar cells sown onto the clothing or be recharged byplacing or hanging the clothing item on a rack or location where it isrecharged wirelessly or inductively. By using inductive charging, theuser does not have to plug in devices into individual wires andconnectors at the appropriate jacket pocket.

In some cases, it may be desirable to build the charger or the secondarypart (receiver for a charger) into the protective case of anotherdevice. For example, many products exist today that are after-market oroptional items such as a skin or case for a music player, phone, PDA, ornotebook computer. In one implementation, the case or skin can containthe electronics and the coil necessary to allow the device to be chargedor charge other devices or both. The charger can be powered by thedevice its attached to or can receive power from a separate source suchas a solar cell, fuel cell, etc. that is integrated with the charger orin another location and electrically connected to the charger. Forexample, in a briefcase, while the charger is inside the briefcase andcan charge devices inside, the surface of the briefcase can have solarcells that would power the charger inside. The briefcase can alsocontain rechargeable batteries that would store power generated by thesolar cells and use them when necessary to charge devices inside.Similarly, the charger can be built on the outside or inside surface ofthe case and charge devices placed on or near the surface.

It is also possible to provide a charger with modular components thatallow other capabilities to be added later or simultaneously as anoption. In one embodiment, an inductive charging pad that contains arechargeable battery can have a separate top surface module or allaround cover or skin that contains a solar cell array and wouldsimultaneously electrically connect to the charger pad to enable thebattery internal to the unit to be charged without any external powerinput. It is also possible to have the cover or the outside skin toprovide other capabilities such as communications, or simply provide adifferent look or texture so that the pad fits in with the user's tasteor décor.

FIG. 22 shows an illustration of a kiosk that incorporates an inductivecharger unit in accordance with an embodiment of the invention. As shownin FIG. 22, the kiosk 390 includes a control screen 392 and an inductivecharging pad 394, to allow individuals to walk-up and purchase anoccasional charge for their mobile device. Currently, the usage model oftypical mobile user consists of charging their most essential device(phone. MP3 player, Bluetooth headset, etc.) during the night or at theoffice or car. In cases where the user is outside their environment fora long time such as traveling, this may not be possible. A variety ofpublic mobile device charging stations have appeared that allow the userto charge their device in a public setting by paying a fee. An inductiveor wire free public charging station or kiosk would allow the user toplace their mobile device that is ‘enabled’ (i.e. has the appropriatereceiver or components to allow it to receive power from the charger) onor in the wire free or inductive charger station and charge the device.The customer can pay for the service or receive the service for freedepending on the service providers' approach. The payment can be cash,credit card, debit card, or other methods.

In accordance with an embodiment, a single pad with multiple stationscan charge multiplicity of devices simultaneously. The user may be askedto pay for the service before charging a device or the service may befor free. Alternatively, each charging station can be in a compartmentand the device is secured by a door that can only be opened through acode given to the device owner when charging starts or payment occurs.The door can also be secured by a combination lock or physical key.

Alternatively, the charging station or kiosk can be open and notphysically secure but when the user pays for the service, a code isissued. The user proceeds to place their device to be charged but whenthe charging ends or the user wants to pick up the device, the code mustbe entered first. If no code is entered, an alarm is sounded or thedevice is deactivated or some other warning occurs. In this way, a thiefor the wrong user can not remove the device without attracting attentionthat may act as a deterrent. A combination of the above techniques maybe used in implementing a public charging kiosk.

Since a typical charging process can take up to 30 minutes or more, itis possible to also synchronize data, download songs, movies, etc. intothe device during this time. Many of current mobile devices haveBluetooth or WiFi capability. Other communication protocols such asWiMax can increase the data rate further. By combining the charging andinformation transfer process, the service provider can charge foradditional services. In addition, if a camera is being charged and haswireless capability, it can download the pictures or movies to adesignated website or online storage area or be emailed to a designatedemail address while charging. In this way, a traveler can simultaneouslycharge a camera while downloading the contents of its memory to alocation with larger memory. This would enable the traveler to free uplimited memory space in their camera or other mobile device. Such aservice would enable devices that have limited or short range wirelesscommunication capabilities (such as mobile phones, MP3 players, cameras,etc) to be able to connect to the internet and send or receive dataindirectly. It is important to recognize that without the chargingcapability, a device conducting such downloading or synchronizationthrough an intermediate device (Bluetooth to internet gateway forexample) would often run out of power due to the length of time thiswould take. In this manner the charging capability of the kiosk enablesa more effective operation.

The foregoing description of the present invention has been provided forthe purposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise forms disclosed. Theembodiments were chosen and described in order to best explain theprinciples of the invention and its practical application, therebyenabling others skilled in the art to understand the invention forvarious embodiments and with various modifications that are suited tothe particular use contemplated. It is intended that the scope of theinvention be defined by the following claims and their equivalence.

Some aspects of the present invention may be conveniently implementedusing a conventional general purpose or a specialized digital computer,microprocessor, or electronic circuitry programmed according to theteachings of the present disclosure. Appropriate software coding canreadily be prepared by skilled programmers and circuit designers basedon the teachings of the present disclosure, as will be apparent to thoseskilled in the art.

In some embodiments, the present invention includes a computer programproduct which is a storage medium (media) having instructions storedthereon/in which can be used to program a computer to perform any of theprocesses of the present invention. The storage medium can include, butis not limited to, any type of disk including floppy disks, opticaldiscs, DVD, CD-ROMs, microdrive, and magneto-optical disks, ROMs, RAMs,EPROMs. EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic or opticalcards, nanosystems (including molecular memory ICs), or any type ofmedia or device suitable for storing instructions and/or data.

The foregoing description of the present invention has been provided forthe purposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise forms disclosed.Many modifications and variations will be apparent to the practitionerskilled in the art. Particularly, while the embodiments of the systemsand methods described above are described in the context of chargingpads, it will be evident that the system and methods may be used withother types of chargers. Similarly, while the embodiments describedabove are described in the context of charging mobile devices, othertypes of devices can be used. The embodiments were chosen and describedin order to best explain the principles of the invention and itspractical application, thereby enabling others skilled in the art tounderstand the invention for various embodiments and with variousmodifications that are suited to the particular use contemplated. It isintended that the scope of the invention be defined by the followingclaims and their equivalence.

1-20. (canceled)
 21. A system for providing power inductively to aportable device comprising a battery and an inductive receiver unitincluding a receiver coil and a receiver circuit, the system comprising:a first primary coil that is substantially planar and parallel to asurface of the system for providing power inductively to the portabledevice; a first drive circuit, including a FET driver, a capacitor, anda FET switch, coupled to a DC voltage input and coupled to the primarycoil, wherein the drive circuit is configured to apply an alternatingelectrical current to the primary coil at an operating frequency andduty cycle to generate a magnetic field in a direction substantiallyperpendicular to the plane of the primary coil and the surface of thesystem to provide power inductively to the portable device when thereceiver coil of the portable device is close enough to the primary coilto receive power inductively from the primary coil; a first sensecircuit to monitor current flow through the primary coil duringoperation of the drive circuit to sense current modulation in theprimary coil from modulation of current in the receiver coil; and acommunication and control circuit, including a micro control unitcoupled to the drive circuit and the sense circuit, configured to:detect, through the first sense circuit, communication of information inthe current modulation in the primary coil; operate the drive circuit atan operating frequency and a duty cycle to inductively transfersufficient power to the inductive receiver unit to activate and powerthe receiver circuit to enable the receiver circuit to communicate theinformation in the current modulation in the primary coil, wherein thecommunication of information includes information to enable thecommunication and control circuit to configure the provision of powerinductively to the portable device, wherein the received communicationof information includes: information corresponding to a voltage orcurrent induced by the primary coil at an output of the receivercircuit; a unique identification code; a manufacturer code; a chargealgorithm profile; and a power requirement; from the receivedcommunication of information, determine when the receiver coil is closeenough to the primary coil and sufficiently aligned with the primarycoil for the system to inductively transfer the power from the primarycoil to the receiver coil to charge the battery of the portable device;and operate the drive circuit according to the power requirement andcharge algorithm profile to provide the power from the primary coil tothe receiver coil to power the receiver unit and charge the battery ofthe portable device, wherein to charge the battery of the portabledevice the communication and control circuit is further configured to:receive additional information in the current modulation in the primarycoil from the modulation of the current in the receiver coilcorresponding to the voltage or current at the output of the receivercircuit while charging the battery of the portable device; regulate in aclosed loop feedback manner the voltage or current at the output of thereceiver circuit in accordance with the received additional informationcorresponding to the voltage or current at the output of the receivercircuit by adjusting at least one of the operating frequency and theduty cycle of the drive circuit during charging of the battery of theportable device; monitor for continued presence of the portable deviceand completion of the charging of the battery of the portable devicebased on the communication from the receiver circuit and detected by thecommunication and control circuit through the first sense circuit; andif the portable device is no longer present or charging is complete,stop operation of the drive circuit for the provision of powerinductively to the portable device.
 22. The system of claim 21, whereinthe communication and control circuit is further configured to adjustthe DC voltage input to the drive circuit.
 23. The system of claim 21further comprising: a second primary coil; a second drive circuit,coupled to the second primary coil; a second sense circuit, coupled tothe second primary coil; and wherein the communication and controlcircuit is coupled to the second drive circuit and the second sensecircuit and is configured to provide power inductively to the portabledevice and one or more additional portable devices simultaneously. 24.The system of claim 21 wherein the system includes at least a secondprimary coil and further wherein the system is configured to separatelydrive each of the primary coils, and, depending on the communicationreceived from the receiver unit, select and drive a subset of theprimary coils to provide power inductively to the portable device. 25.The system of claim 24 wherein the system is configured to select asubset of the primary coils based on comparison of voltage or currentinformation received from the receiver unit through each of the primarycoils.
 26. The system of claim 24 wherein the system is configured toselect a subset of primary coils based on a power requirement of thereceiver unit.
 27. The system of claim 21 wherein the system includesmultiple primary coils of different sizes which the system is configuredto drive separately to provide different power levels to the portabledevice and additional portable devices in accordance with powerrequirements of each of the portable devices.
 28. The system of claim 21further including a magnet at a center of the primary coil wherein themagnet is magnetized in a direction perpendicular to the surface of thesystem to assist in alignment of the receiver coil with the primary coilfor inductively powering and charging the portable device.
 29. Thesystem of claim 21 wherein the system is included as part of a mobilephone.
 30. The system of claim 21, further wherein the communication andcontrol circuit is configured to operate the drive circuit for a shortperiod of time to detect a current draw through the primary coilindicating a possible presence of the portable device for charging,wherein the short period of time is less than that needed to activateand power a receiver unit in a compatible portable device.
 31. Thesystem of claim 21, wherein the communication of information generatedby the receiver circuit and the additional information is encrypted forsecurity, and the communication and control circuit is configured toprocess the encrypted information and the additional information. 32.The system of claim 21, wherein the primary coil comprises a flexiblePrinted Circuit Board (PCB) coil with multiple layers of conductors ofcoil patterns electrically connected with vias between the layers. 33.The system of claim 32, wherein the multiple layers of conductors ofcoil patterns have a substantially similar coil pattern.
 34. The systemof claim 33, wherein each of the coil patterns includes 1 to 4 ounce(oz) copper thickness.
 35. The system of claim 34, wherein the PCBincludes a near field communication (NFC) antenna for communication ofdata.
 36. The system of claim 21, wherein the system is built into alaptop computer to provide an inductive charging section.
 37. The systemof claim 21, wherein the system further comprises a section toinductively receive power from a charger using the first primary coil.38. A portable device including a battery and a receiver unit capable ofreceiving inductive power from a compatible inductive charging systemincluding a base unit with a primary coil and associated circuit, thereceiver unit comprising: a receiver coil which has a substantiallyplanar shape and is located parallel to a surface of the portable deviceso that a magnetic field, when received through the surface of theportable device from the primary coil in the base unit of the compatibleinductive charging system in a direction substantially perpendicular tothe plane of the receiver coil, inductively generates a current in thereceiver coil to provide power inductively to the portable device whenthe portable device is placed on the base unit for charging the batteryof the portable device; a ferrite material layer placed under thereceiver coil on a side of the receiver coil opposite to the surface ofthe portable device; a receiver circuit powered by the inductivecharging system, wherein the receiver circuit comprises: a receiverrectifier circuit including a rectifier and a capacitor; and a receivercommunication and control circuit including a micro control unit tomodulate the current in the receiver coil to communicate with the baseunit while the receiver circuit is being powered by the inductivecharging system; wherein when a current is generated in the receivercoil inductively by the primary coil in the base unit, the current isrectified and smoothed by the rectifier circuit and is used to power andactivate the receiver communication and control circuit and to chargethe battery of the portable device; and wherein upon powering andactivation of the receiver circuit by the primary coil in the base unit,the receiver circuit is configured to: communicate to the base unit avoltage or current value at an output of the receiver rectifier circuitinduced by the primary coil, a unique identifier code, a manufacturercode, a charge algorithm profile, and a power requirement; andperiodically communicate to the base unit information corresponding to apresently induced output voltage or current of the receiver rectifiercircuit to enable the base unit to regulate in a closed loop manner theoutput voltage or current of the receiver rectifier circuit during thecharging of the portable device.
 39. The portable device of claim 38,wherein the receiver coil is constructed of a flexible Printed CircuitBoard (PCB) comprising multiple metallic layers connected by vias. 40.The portable device of claim 38, wherein the receiver circuit furthercomprises: a limiter coupled to the output of the receiver rectifiercircuit to limit the output voltage of the receiver rectifier circuit toa maximum value; and a battery charging circuit, wherein the batterycharging circuit is coupled to the output of the receiver rectifiercircuit and coupled to the battery to charge the battery, wherein thebattery charging circuit is configured to begin drawing current from thereceiver rectifier circuit only when the output of the receiverrectifier circuit reaches a set start voltage value.
 41. The portabledevice of claim 38, further comprising a base unit circuit to enable theportable device to operate as an inductive charger using the receivercoil of the portable device to inductively power and charge anotherportable device.
 42. The portable device of claim 38, wherein thereceiver coil further comprises a separate NFC antenna for communicationof data.
 43. The portable device of claim 38 further comprising thesystem of claim 1 wherein the battery can be used to operate the systemand further including NFC and Bluetooth communication capabilities. 44.The portable device of claim 43 wherein the primary coil and thereceiver coil are the same.
 45. The portable device of claim 44 whereinthe portable device is a mobile phone configured to notify the userthrough messages on the device display that inductive charging isoccurring and the degree of battery charge.
 46. The portable device ofclaim 38 wherein the portable device comprises circuitry and a displayto notify the user through messages on the device display and audiblythat inductive charging is occurring and display the degree of batterycharge.
 47. A system for providing power inductively to a portabledevice comprising a battery and an inductive receiver unit including areceiver coil and a receiver circuit, the system comprising: a primarycoil that is substantially planar and parallel to a surface of thesystem for providing power inductively to the portable device, whereinthe primary coil comprises a flexible Printed Circuit Board (PCB) coilwith multiple layers of conductors of coil patterns electricallyconnected with vias between the layers; a drive circuit, including a FETdriver, a capacitor and a FET switch, coupled to a DC voltage input andcoupled to the primary coil, wherein the drive circuit is configured toapply an alternating electrical current to the primary coil at anoperating frequency and duty cycle to generate a magnetic field in adirection substantially perpendicular to the plane of the primary coiland the surface of the system to provide power inductively to theportable device when the receiver coil of the portable device is closeenough to the primary coil for inductive power transfer; a sense circuitto monitor current flow through the primary coil during operation of thedrive circuit to sense a current modulation in the primary coil from amodulation of a current in the receiver coil; and a communication andcontrol circuit, including a micro control unit coupled to the drivecircuit and the sense circuit, configured to: detect, through the sensecircuit, communication of information in the current modulation in theprimary coil; operate the drive circuit at an operating frequency and aduty cycle to inductively transfer sufficient power to the inductivereceiver unit to activate and power the receiver circuit to enable thereceiver circuit to communicate the information in the currentmodulation in the primary coil; from the information communicated by thereceiver circuit, determine if the system can provide power inductivelyfrom the primary coil to the receiver coil to charge the battery of theportable device and determine a power requirement; and operate the drivecircuit according to the power requirement to provide power inductivelyfrom the primary coil to the receiver coil to power the receiver unitand to charge the battery of the portable device, wherein to charge thebattery of the portable device the communication and control circuit isfurther configured to: receive additional information in the currentmodulation in the primary coil from modulation of the current in thereceiver coil corresponding to a voltage or current at an output of thereceiver circuit while charging the battery of the portable device; andregulate in a closed loop feedback manner the voltage or current at theoutput of the receiver circuit in accordance with the receivedadditional information corresponding to the voltage or current at theoutput of the receiver circuit by adjusting at least one of theoperating frequency and the duty cycle of the drive circuit duringcharging of the battery of the portable device.
 48. A system forproviding power inductively to a compatible portable device comprising abattery and an inductive receiver unit including a receiver coil and areceiver circuit, the system comprising: a system rechargeable battery;an inductive coil that is substantially planar and parallel to a surfaceof the system for providing power inductively and for receiving powerinductively, wherein the inductive coil is formed in a flexible printedcircuit board (PCB) and includes multiple conducting coil layersconnected by vias; a drive circuit, including a FET driver, a FETswitch, and a capacitor, coupled to the inductive coil, wherein thedrive circuit is configured to switch a DC input voltage coupled to theFET switch at a frequency and a duty cycle to apply an alternatingelectrical current to the inductive coil to generate a magnetic field ina direction substantially perpendicular to a plane of the inductive coiland the surface of the system to provide power inductively to a portabledevice when near the inductive coil; a sense circuit to monitor currentflow through the inductive coil during operation of the drive circuit tosense a current modulation in the inductive coil from a modulation of acurrent in the receiver coil caused by the receiver circuit; acommunication and control circuit including a micro control unit, thecommunication and control circuit coupled to the drive circuit and thesense circuit to detect communication of information in the currentmodulation sensed by the sense circuit via the inductive coil duringoperation of the drive circuit to control provision of power inductivelyto the portable device; a receiver rectifier circuit, including arectifier and a capacitor, coupled to the system rechargeable batteryand the inductive coil, to receive power inductively from a wirelesscharger via the inductive coil to charge the system rechargeable batterywirelessly; and a wired power input coupled to the system rechargeablebattery configured to charge the system rechargeable battery by a wiredconnection; wherein: the DC input voltage coupled to the FET switch ispowered by at least one of the system rechargeable battery and the wiredpower input; and to provide power inductively to the portable device,the communication and control circuit is configured to: operate thedrive circuit at a frequency and a duty cycle for a period of time totransfer sufficient power to the inductive receiver unit of the portabledevice to activate and power the receiver circuit of the portable deviceto enable the receiver circuit to communicate with the system throughthe current modulation in the inductive coil so that the system canconfigure inductive power provision to the portable device; from thecommunication of information from the inductive receiver unit, determinewhether the portable device is present and the battery of the portabledevice is chargeable with the inductive coil and determine a powerrequirement; and operate the drive circuit according to the determinedpower requirement to transfer power via the inductive coil to thereceiver coil to charge the battery of the portable device, wherein tocharge the battery of the portable device the communication and controlcircuit is further configured to: periodically receive additionalcommunication from the inductive receiver unit via the inductive coiland the sense circuit of a voltage or current at an output of thereceiver circuit while charging the battery of the portable device; andregulate in a closed loop feedback manner the voltage or current at theoutput of the receiver circuit by adjusting at least one of thefrequency and duty cycle of the drive circuit during the charging of thebattery of the portable device.
 49. The system of claim 48, furthercomprising: a near field communication (NFC) antenna for communicationof data; and a battery charging circuit coupled to an output of thereceiver rectifier circuit and coupled to the system rechargeablebattery, to charge the system rechargeable battery, wherein the batterycharging circuit is configured to begin drawing current from theinductive coil only when the output of the receiver rectifier circuitreaches a set start voltage value.
 50. The system of claim 48, whereinthe DC input voltage coupled to the FET switch is configured to at leastoccasionally be powered by the system rechargeable battery.